Authentication Bypass Affecting oauth2-proxy package, versions <0:7.15.4-0.1.hum1


Severity

Recommended
0.0
high
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.73% (53rd percentile)

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  • Snyk IDSNYK-RHEL10-OAUTH2PROXY-20037110
  • published22 Sept 2026
  • disclosed21 Apr 2026

Introduced: 21 Apr 2026

CVE-2026-40575  (opens in a new tab)
CWE-290  (opens in a new tab)

How to fix?

Upgrade RHEL:10 oauth2-proxy to version 0:7.15.4-0.1.hum1 or higher.
This issue was patched in RHSA-2026:58471.

NVD Description

Note: Versions mentioned in the description apply only to the upstream oauth2-proxy package and not the oauth2-proxy package as distributed by RHEL. See How to fix? for RHEL:10 relevant fixed versions and status.

OAuth2 Proxy is a reverse proxy that provides authentication using OAuth2 providers. Versions 7.5.0 through 7.15.1 may trust a client-supplied X-Forwarded-Uri header when --reverse-proxy is enabled and --skip-auth-regex or --skip-auth-route is configured. An attacker can spoof this header so OAuth2 Proxy evaluates authentication and skip-auth rules against a different path than the one actually sent to the upstream application. This can result in an unauthenticated remote attacker bypassing authentication and accessing protected routes without a valid session. Impacted users are deployments that run oauth2-proxy with --reverse-proxy enabled and configure at least one --skip-auth-regex or --skip-auth-route rule. This issue is patched in v7.15.2. Some workarounds are available for those who cannot upgrade immediately. Strip any client-provided X-Forwarded-Uri header at the reverse proxy or load balancer level; explicitly overwrite X-Forwarded-Uri with the actual request URI before forwarding requests to OAuth2 Proxy; restrict direct client access to OAuth2 Proxy so it can only be reached through a trusted reverse proxy; and/or remove or narrow --skip-auth-regex / --skip-auth-route rules where possible. For nginx-based deployments, ensure X-Forwarded-Uri is set by nginx and not passed through from the client.

CVSS Base Scores

version 3.1